Convert 4K video to 1080p — or upscale to 4K
A single minute of 4K phone video usually takes roughly 150 to 450 megabytes, depending on the frame rate and codec, and plenty of laptops, older TVs, editing apps and upload forms struggle with it. This 4K video converter turns 3840 × 2160 video into 1080p or 720p — a quarter or a ninth of the pixels — which plays everywhere and makes a far smaller file. It can also go the other way and upscale 1080p material to 2160p when a platform insists on 4K.
Pick the codec to suit where the video is going: H.264 for maximum compatibility, HEVC (H.265) for similar quality at roughly half the bitrate, or AV1 for the smallest files on modern devices. Everything runs in your browser with WebCodecs and the Mediabunny library (MPL-2.0) — 4K files are never uploaded, which also saves you the long wait for a big upload.
How to use the 4K Video Converter
- Drop the 4K video (MP4 or MOV from a phone, drone or camera, or a WebM or MKV file) on the upload area. The details show its resolution, codec and frame rate.
- Choose the target: 1080p (Full HD) for most uses, 720p (HD) for the smallest files, 1440p (QHD) as a middle ground, or 2160p (4K) to upscale a smaller video.
- Under “Save as” choose MP4 · H.264, MP4 · H.265 (HEVC) or MP4 · AV1. Options your browser cannot encode are marked.
- Keep “Keep the shape” unless you need an exact 16:9 frame, then press “Convert video”.
- Follow the progress bar and time estimate, then compare Before and After and download.
4K Video Converter features
4K to 1080p and 720p
High-quality downscaling with the shape preserved — vertical 4K becomes 1080 × 1920, not a squashed landscape frame.
H.264, HEVC and AV1
Choose maximum compatibility, half-bitrate HEVC or the most efficient AV1 — each checked against your browser before encoding starts.
Upscaling with a clear label
1080p → 2160p is available for platforms that require 4K, with a reminder that it adds pixels, not detail.
Memory-aware
A note appears whenever 4K frames are involved, with advice for phones and tablets where memory is tight.
Progress, estimate and Cancel
See the percentage and the time left, and stop a long job at once.
Never uploaded
Large 4K files stay on your device; there is no upload wait and no server-imposed size limit.
4K vs 1440p vs 1080p vs 720p at a glance
On a phone or a laptop screen at a normal viewing distance, the difference between a well-encoded 1080p copy and the 4K original is often hard to see, which is why 1080p remains the everyday standard for sharing.
| Resolution | Pixels | Share of 4K | Good for |
|---|---|---|---|
| 2160p (4K UHD) | 3840 × 2160 | 100% | Large TVs, room to crop in editing, archiving |
| 1440p (QHD) | 2560 × 1440 | 44% | High-resolution monitors, a lighter master copy |
| 1080p (Full HD) | 1920 × 1080 | 25% | YouTube, laptops, phones, most TVs, sharing |
| 720p (HD) | 1280 × 720 | 11% | Messaging, email, slow connections |
H.264, HEVC or AV1?
- H.264 (AVC) plays on practically every phone, computer, TV and editor in use today. Choose it when you do not know where the video will end up.
- HEVC (H.265) needs roughly half the bitrate of H.264 for similar quality. iPhones record in it, and Apple devices, recent Android phones, most smart TVs and Windows with the HEVC extension play it.
- AV1 is newer and more efficient still. Current Chrome, Edge and Firefox, recent Android phones and newer TVs play it; older devices and some editors cannot.
- Encoding support depends on your browser and hardware. If an option is marked as unsupported, H.264 is the dependable fallback.
Working with 4K in a browser
Each 4K frame holds 8.3 million pixels, four times as many as 1080p, so decoding it takes real memory and processing power. On a recent laptop or desktop a few minutes of 4K usually converts comfortably. On phones and tablets keep clips short, close other apps and keep the screen on, because mobile browsers may stop a tab that uses too much memory. If a job fails, try 720p, a shorter clip or a desktop browser.
For other sizes, use the video resolution converter or the video resizer; for exactly 1920 × 1080 with bars or a crop, the 1080p video converter has the same options.
4K Video Converter FAQ
How do I convert 4K video to 1080p?
Drop the 4K file, keep “1080p (Full HD)” and “Keep the shape” selected, choose MP4 · H.264 and press “Convert video”. A 3840 × 2160 video becomes 1920 × 1080.
Will converting 4K to 1080p reduce quality?
It reduces resolution, which is the point — but because each output pixel is averaged from four source pixels, a 1080p version made from 4K often looks cleaner than footage shot in 1080p. On most screens it looks excellent.
How much smaller is a 1080p file than 4K?
It depends on the codec and quality, but with a quarter of the pixels the 1080p file is typically several times smaller. Choosing HEVC or AV1 shrinks it further.
Can I upscale 1080p video to 4K?
Yes, choose 2160p (4K). The video becomes 3840 × 2160 so it meets 4K requirements, but upscaling cannot add detail that was never recorded.
Why does my phone struggle with 4K videos?
4K frames are large, and decoding and encoding them in a browser uses a lot of memory. Keep clips to a few minutes on phones, close other apps, or use a computer for long files.
Is my video uploaded by the 4K video converter?
No. The conversion happens entirely on your device, so even very large files stay private and there is no upload to wait for.